The objective of this research project is to characterize disruptions of real-time access to lexical information in aphasia. The studies we propose are directed specifically to an analysis of early processing stages in which lexical entries are activated and their meanings and structural properties made available for further processing at the syntactic and semantic levels. Our analyses of lexical activation will take two forms. One set of studies will focus on the time course of activation; a second set, on levels of activation and the role of summation processes within lexical networks. In each case, an attempt will be made to determine if disruptions in these processes are related to the clinical, linguistic, and neuroanatomical characteristics of the aphasic patients tested.